Tuesday, 26 February 2013

Comments on the
discussion section of the Snowling et al articleQuestioning the benefits that coloured overlays can have for
reading in students with and without dyslexia

This Blog contains HTML points where I have made comments on the
discussion taken from the original article.

These points are at the base of the blog.

This
does get a bit detailed. The article was brought to my attention yesterday. I
can send the Urll for the original article as well.

Discussion

This study addressed three important questions relating to visual
stress: (1) Are undergraduate students with dyslexia more likely to experience
visual stress[P1] during reading than
undergraduate students without dyslexia? (2) Does the benefit shown by overlays[P2] in reading
unconnected text extend to reading rate and comprehension of meaningful
connected text? (3) Does the improvement shown by coloured overlays on WRRT
have good reliability?

Although they reported experiencing symptoms of visual stress on a
questionnaire, the students with dyslexia in this sample did not show greater
gains in reading rate with an overlay than controls[P4]. This[P5] finding is
inconsistent with Singleton
and Henderson (2007b) who reported that children with[P6] dyslexia showed
greater gains in reading rate with overlays than controls.

Singleton
and Trotter (2005) reported that only dyslexic adults with visual
stress significantly benefited from overlays in contrast to dyslexic adults
without visual stress, non-dyslexic adults with visual stress, and adults
without either dyslexia or visual stress. However, in the present study, the
correlation between total symptoms reported and improvement in reading rate
with an overlay was weak for controls and not significant for the dyslexic
group. Counter to expectations, this implies that individuals who experience
more symptoms of visual stress do not benefit more from overlays than
individuals who experience few symptoms of visual stress. This finding sparks
concern, suggesting that the two main methods of identifying visual stress may
not lead to the same diagnostic conclusions. Indeed, Wilkins
(2003) stated that ‘. . . sometimes individuals who
show dramatic improvements in reading fluency with a coloured overlay report no
symptoms and show no signs of visual stress’ (p. 18). Visual stress
questionnaires are problematic because many symptoms can be attributed to binocular
vision and accommodative anomalies as well as decoding problems[P7]. Given that
increased rates of visual and oculomotor difficulties have been reported in
individuals with dyslexia (Evans,
1998; 2001; Evans
et al., 1999), the higher scores for the dyslexic group on the
questionnaire may not reflect susceptibility to visual stress, but rather, the
presence of other visual anomalies[P8]. This is problematic
since overlays are frequently distributed[P9] solely on the basis
of symptom questionnaires or subjective beneficial reports of coloured overlays
or lenses without a formal assessment of optometric function[P10].

Consistent with Ritchie et al., 2011, we found that neither reading
comprehension nor rate of reading connected text was improved by overlays in either
group. This[P11] finding questions the value of overlays for
reading naturalistic texts. While it is important for the present results to be
replicated using a wider variety of passages of varying difficulty, the results
question the value that overlays can[P12] have for undergraduate students with or without
dyslexia.

The dyslexic group showed slower reading rate overall. Moreover, there
was a significant negative correlation between reading rate without an overlay
and the improvement shown in reading rate with an overlay for both groups. A
linear relationship has been reported between baseline latency and difference
scores (Chapman,
Chapman and Curran et al., 1994), suggesting that the size of
improvement in reading rate with an overlay on WRRT is confounded by baseline
reading rate. Thus, individuals with dyslexia who have a slower reading rate
without an overlay have more ‘room for improvement’ than individuals who start
out with faster baseline reading rate. This may inflate the improvement scores
and account for previous findings that dyslexics show larger improvements in
reading rate with an overlay than controls[P13]. Hence, caution should be taken when using such
difference scores as a diagnostic indicator, particularly with dyslexic
readers.

We also carried out a preliminary investigation of the reliability of
overlay testing using the WRRT in undergraduates with and without dyslexia.
This issue is particularly important given that overlay testing with WRRT is
often used as a means to identify visual stress[P14] as well as being the primary treatment method.
Both groups read more words per minute in Phase 2 than in Phase 1, suggesting
that reading rate on WRRT increases with practice. Although the test–retest
reliability of reading without an overlay was strong for both
groups, consistent with Wilkins
et al., 1996; Wilkins
et al., 2001, the reliability coefficients for the improvement in
reading with overlays were weak. Mean overlay improvement did not significantly
differ in Phase 1 and 2 for the controls[P15], but was significantly reduced for the dyslexic
group in Phase 2. These results suggest that this means of testing for the
benefit of overlays is not reliable when used with young adults. Although the
present sample may have contained only a handful of individuals with visual
stress, the test–retest reliability of assessment procedures[P16] should be high regardless of the sample to be
tested.

None of the previous studies that have used the immediate benefit
criterion have examined the same participants twice in a month as in this
study. Wilkins
et al. (2001) examined children after 8 months of sustained
use, and Jeanes
et al. (1997) tested children after 3 and 10 months of
sustained voluntary use[P17]. Therefore, these participants had been using
overlays for prolonged periods which could have increased the test–retest
reliability. Nevertheless, any measure which is used as a diagnostic tool
should strive for strong reliability. Although it is important to emphasise the
preliminary nature of the present findings and that the reliability
coefficients reported here must be replicated in studies with larger samples,
one would have anticipated greater agreement between the improvement scores in
Phase 1 and 2.

The benefit shown from overlays on WRRT significantly decreased in Phase
2 for the dyslexic group but not for the control group. The improvement scores
may have been inflated at Phase 1 because of the lower baseline reading rate in
this group (Chapman
et al., 1994). An alternative explanation could be that
individuals with dyslexia are more prone to novelty effects than controls and
that these decrease with repeated exposure. This is particularly likely if the
students with dyslexia were aware that overlays are known to aid reading
fluency. Indeed, a large proportion (56%) of the dyslexic students had
previously been provided with coloured overlays. In the light of the present
results, this practice raises concern[P18].

In conclusion, visual stress remains[P19] a controversial subject. The dyslexic undergraduates
in this study reported experiencing significantly more symptoms of visual
stress than undergraduates without dyslexia. However, it remains unclear
whether these symptoms were solely attributable to visual stress, or rather to
other visual anomalies. All participants read faster with an overlay than
without, however, in contrast with previous findings, undergraduates with
dyslexia did not benefit from coloured overlays to a greater extent than
undergraduates without dyslexia. Furthermore, benefit in reading rate with an
overlay did not extend to reading connected text or to reading comprehension,
questioning the practical value of coloured overlays as[P20] a remediation for reading difficulties. Finally,
the improvement in reading rate with an overlay was not consistent over time
and can therefore not be regarded as a reliable indicator of visual stress[P21] for dyslexic students. The findings from this
study question the use of coloured overlays as a means of identifying or
treating visual stress[P22] as a remediation for reading difficulties. A
limitation of our study was the small sample size and the possibility that the
students tested were not representative of all those studying in higher
education. Although our findings are in need of replication with a larger sample,
our results, together with the lack of causal evidence highlighted by previous
reviews, suggest that great care should be taken before recommending coloured
overlays in the remediation of dyslexia[P23].

[P1]Jim
Gilchrist at Bradford Optometry would have prefer to distinguish between ophthalmic originating
visual stress and pattern-related visual stress. I tend to agree with this
although it is difficult to identify causation at a ‘sympton identification
stage.

[P2]This
relates to the use of Intuitive Overlays and the forced choice protocols to
identify a ‘preference’ These overlays were designed for research purposes not
clinical purposes. And I would suggest too coarse anyway.

[P3]Reading
rate is an interesting concept. Assuming this to be a reading aloud rate of
Random text as in the Wilkins rate of reading?

[P4]If
we take a ‘Limiting factors model’ for a person reading, this suggests that
even if it did help there were other limiting factors at play in most
individuals. I.e. the reported and presumably reduced visual stress symptoms were
not affecting rate. Though it may hav affected reading stamina. Very important I
studying.

[P6]It
is now understood that automaticity develops with age . With children below say
10 years old the visual span is most likely limiting speed in those with slow
reading development.Perceptual span increases with automaticity.. I think. SoI
would suggest that this is a likely outcome.

[P7]As
above there is an overlap in causality likely here. Also so many people do not
identify the symptoms as ‘stress’ they think of them as norma;’mor have
developed strategies associated with reading which avoids getting to the point where
their systemdoes not reach ‘tipping points’ and the symptoms are triggered.

[P8]Using
an eye tracker a common response to ophthalmic issues is to suppress an eye so
the person effectively becomes monocular. This gives rise to dyspraxic type
symptoms associated with reading although it can also give rise to attention
management problems since the ‘suppressed eye may well drift sideways away from
the text target. Then any image movement on the retina of the suppressed eye
will give a reflexive saccade to the moving object and could suppress the image from the reading
eye.

[P9]To
be honest the protocols used rarely
follow those recommended. It takes about 20minutes to 30minutes to follow the
protocols carefully and can be very confusing to the tester. So there is a
tendency to almost randomness in my opinion.
That was the reason I went over to a measurement based system rather
than intuitive much to the annoyance of colleagues at the time.

[P10]Most
dyslexic undergraduates have a long history of optometric/ophthalmic support (
from our data) but in my opinion not sufficiently rigorous on too many
occasions.

[P11]This
is like comparing chalk and cheese as they say!
The protocols and materials are not comparable. Arnold designed the |Intuitive
overlays because of questions of design and functionality with the Irlen approach. Perhaps we should have compared the use of
Sharps toffee papers, they have different coloured sellophane too!

[P12]I
agree I think that the question is more about what value the protocols used in
this study have.

[P13]I
am more interested in the distribution of the ranges of reading ratemin the
populations in that a biophysics perspective can kick in. For example there are certain speeds that
are consistent across studies.

[P14]I
honestly cannot understand this statement. Why on earth do this? Who does?

[P15]That
was the reason why in 1999 IO decided to move to an objective choice process
rather than the forced choice protocols. and then to more precise computer
based identification in 2000. We were racking students longitudinally. Some
students returning four or five times.

[P16]This
does depend on the assumption that there is no ‘therapeutic component. Not that
I am claiming there is. But with an objective approach for many students that
appears to happen which could well be a consequence , if everything is done
well, of increased visual span, possibly from a reduction in crowding ( jury is
out on that at the moment.) or from increased perceptual span as a consequence
of serial processing of more visual spans within a fixation and a consequential
or associated reduction in demand on working memory with a release of more
resources in the central executive for other function.. My hypothesis J

[P17]This
is a very important point Although test-retest is a study of the protocols
rather than the concept behind the idea. So perhaps this should be reflected in
the title of the report.

[P18]The
longitudinal aspects of this study as compared with studies with younger people are so different that placebo effects could not
be ruled out. Or indeed any Thompson effects ( I think I know what I mean
there,, correct me if I am wrong.)

[P19]On
that the many people involved in using the term have little or know idea about
the biology of reading and as such this is a problem of Hegelian Dialectics. There is not a real conversation taking
place. Each person or group of people has their own mental construct of the
concept and as such cannot understand or agree with each other. So this discussion
is fundamentally flawed and we need a real symposium on the issue. Hopefully a
rational consensus might emerge. In Biology a ‘stressed system’ can be defined.
This is not really psychology though.

[P20]No.
This questions the value of the
protocols and materials used in this study.

[P21]I
really cannot get my head around this sort of statement. It is really a
nonsense to think it was in the first place!

[P22]The
word #treating’ implies that ‘visual stress’ this is a disorder. a disease. To
me this is the same as saying a person running in shoes that are the wrong
design, finding running difficult or slow is experiencing a disability/
disorder which is called ‘running stress’

Sunday, 24 February 2013

Twelve
years ago, on the suggestion of a colleague of hers. I used rapid digit naming as an alternative to
rapid automatic naming of text to find out how the dyslexic students were
performing compared with non-dyslexic adults. As Uta reported the mean for the
dyslexic students was around 135 digits
per minute.

The same as for rapid word naming.
The inference in her research was that this was evidence for a
phonological deficit.

However when the students were asked to
undertake RDN using their optimal settings on the computer screen their performance
average 184 digits per minute which was the same s the RAN mean of non-dyslexic
students.

It was
also the same as reported for RDN by Uta for the non-dyslexic students at
University College.

The question I ask is this.

If the Phonological processing is apparently
controlled by the visual image, which one is controlling the reading performance?

Thursday, 21 February 2013

As some of
you have already seen, yesterday I was working with a fellow professional,
taking her reading performance ‘to another level’.

Sandra was
in a way very typical of many dyslexic adults, in that she had been taught and
had learnt strategies to enable her cope and thrive despite the world appearing
to be a very unfriendly place for someone who had to live with a contrast
between the way she was seen by others and her own inner feelings about her
capability.

In Sandra’s
case this has led to explore, to and to assist many other adults. As she has
navigated her way through, she has been able and is able to help others on the journey.

Today I
shall work with a young man who from what I understand, has not been as
successful yet. He has sort of accepted the world’s view of him, or at least
that is what I think is so. I shall find out this afternoon.

With his permission,
I hope, we shall all be able to understand where he is and where he could go
to. Well I hope so. We not make any progress.

What
fascinates me is how few other professionals in this area really seem to want
to know about this stuff.

I like the
fact that I can audit progress and benefit. I like the fact that the biological
model being applied is so consistent in its outcomes. I can conjecture on
mechanisms and to some extent can explore them further, but this work is driven
by a ‘technological loop’ rather than a science loop. The mathematics of the model is complex in
that it is about a complex system where cause, correlation and effect can get
confused. A typical biological system.

It reminds
me of agriculture. Farming appears to be a mixture of science and art. The desired output can be seen simplistically
as ‘tons of product per acre’. Farmers vary the inputs based on what is
perceived to be the ‘limiting factor’ controlling the output. But across a
field there are huge variations in conditions. The needs of individual plants
can be lost.

Short term
need by society might be in conflict with long term need, such as maintenance
of soil structure, soil fertility, reduction in the fossil fuel energy
investment needed to get the food produced.

The evidence
base on which farmers make their decisions is a mix of science and experience.
The science research usually originated from observations, anecdotal evidence
which then gets investigated ‘scientifically’.
For example we know that fungi and bacteria associate with plant roots
to provide nutrients to the plant such as Nitrates, Phosphates and trace
elements. But it is easier to do ‘the science’ of how much of these fertilisers
we add every year rather than how do we nurture the fungi and bacteria which
will provide the crops with their needs. The latter will probably give us a
better, bigger crop without the massive investment in fossil fuels of the
present ‘science based’ methods. If you are interested google ‘permaculture’
and find out more.

What I do
and many others is to gather and apply evidence from case studies which can feed
back to science based research. This all occurs within the context of ongoing
research and at present seems to not be on conflict with the outcomes of research.

So another
one today.

Perhaps I am a bit like a motor racing engineer checking if the
technology will work today in another grand prix?

Wednesday, 20 February 2013

What can really be done to enable a dyslexic adult? Today’s report on Sandra Fox

Sandra is a professional supporting disabled students. We decided last year to see just what can be done to enable a severely dyslexic adult.

Last September we had a preliminary meeting which showed that there was a correctible ophthalmic component to her difficulties. This was despite the prescription she already had. It was a clear issue which showed up with discussion, minimal testing and from use of the binocular eye tracker.

In September we calculated an optimal computer background setting and decided that we would arrange for Sandra to be seen by an ophthalmologist I have been collaborating with.

Today 6 months later Sandra saw my colleague and we had confirmation about her condition and calculation of what prescription was needed.

I then retested her for optimal computer settings.

Below are some details about the outcomes. We wait excited to find out what happens when we finally have the correct glasses for her.

Watch this space.

There is a video on U-Tube showing the original consultation.

There will be detailed report coming soon

___________________________________________________________

The graph
below shows Sandra’s reading on a default computer screen on September 14th
2012.

37.575
seconds for 85 words 494 characters 120 fixations.

4.11
characters per fixation

313
milliseconds per fixation

136 words
per minute

The graph
below shows Sandra’s reading using her optimal conditions but without her
optimal glasses on February 20th 2013.

12.84
seconds for 88 words. 515 characters. 50
fixations

10.03
characters per fixation.

257
milliseconds per fixation

411 words
per minute

What will happen when she has her
perfect pair of glasses?

Please keep in mind my comments on crowding, visual attentions span and perceptual span in the last blog.

Tuesday, 19 February 2013

What is controlling the reading performance in adults? Crowding? Visual
attention span?

Ok so what really controls how well
an adult can read?

‘Reading well’ is an interesting idea.

Is it….

· How fast a person
can read?

· How long a person
can read for?

· How well they
understand what they have read?

· How well they
enjoy what they read?

Research on reading performance it is often reduced down to the
number of words which can be read correctly per minute. But many people can
read faster than people who understand the ideas in the reading better than
them. So the idea of intelligence gets drafted in. But the meaning of the word
‘intelligence’ is not really fixed so we have discussions and research using
lots of imprecise words.

I want to use an idea of ‘effective reading performance’.(ERF) I want
this ERF to somehow be independent of the level of education , culture or
language sophistication of the person.

ERF needs to be a measure of how fast a person can read a set of instructions
to correctly undertake a simple task. So the ERF will involve the
effective interpretation of text to as quickly as possible .

So what will control how fast and accurately the reading will take
place? There appears to be strong evidence that in adults their
‘reading speed’ is no longer dependent on phonological processing unlike when
they were young.

Visual attention span (VAS)

Visual attention span (VAS) is a measure of the number of
letters which can be processed / identified at the same time as each other when
a person looks at a string of letters, a word

In young children there appears to be evidence building up that visual
attention span (VAS) may have a controlling effect on the development
of their phonological understanding, rather than the other way round, which has
been argued in the past.

.

Perceptual span (PS).

This is the number of letters you can see
without moving your eyes when looking at a string of letters

This is not quite the same as VAS
when looking at a string of letters. You could describe it as how many VAS you can
process in one fixation.

Crowding effects

The way the presence of letters and proximity of letters nearby, affect
the speed and correct of recognition of a letter.

Evidences

1.That how large the
letters are in words can affect how easily the letters in words are identified

2.That how easily the
letters in words are identified can be affect ed by how close they are to
each other. .

3.The proximity of
lines of text above and below the one being read can affect how easily the line
being read is identified.

4.The proximity of
words to each other (the gap between words) can affect how easily the word will
be identified.

5.The spatial
regularity (pattern nature) of the words around the word affects how
easily the word will be identified. (pattern related visual stress.. PRVS)

· .

· .

These are just five variables that are fixed in printed text.
Evidence suggests that what each person (the distances/proximities/size) needs
to maximise their reading speed is personal to them. The phenomenon
being referred to here is crowding.

Here the word ‘easily’ is being used to mean how many milliseconds to identify the word. A
measure of speed of processing or perhaps a measure of how little ‘computing
power’ or memory us needed.

So let’s think about the way crowding and VAS and PS may
interact when reading.

When using a binocular eyetracker to study the way an
adult’s eye move when they are reading certain things become obvious.

1.An accomplished
reader needs fewer stops/fixations/photographs to get through a sentence than a
‘poor reader’.

2.An accomplished
reader processes more characters/letters per stop/fixation/photograph than an
accomplished reader.

3.An accomplished
reader takes a shorter time to process each letter/character than a poor
reader.

4.Everyone’s eyes
appear to stop/fixate/photograph around 4 times a second.

So what we need to do
is to find out if it is possible increase the speed of processing of the
letters.

Either as more letters processed at a time (VAS) or/and
fewer milliseconds to process each group (VAS) of letters so
that more letters can be processed in each fixation. An increased perceptual
span (PS)

The VAS will
control how big a word is (number of letters) which can be parallel processed. VAS will
then influence the ability to recognise and blend the phonemes within a word.
Giving rise to a sense of fluency and then intonation.

If VAS is
very restricted then the person is unlikely to achieve a fluency of delivery
when reading aloud or in their ‘inner voice’ when reading silently.

If the VAS is
processed very quickly then it may be possible to hold in memory (Increased PS) the phonemic components of a word
and still blend them hence achieving a higher level of fluency/intonation.

The time needed to process each group of letters (The VAS) is appears to
be associated with automaticity. The greater the reading experience
the lower the amount of spatial (edge) detail needed to identify the letter
string.

Crowding affects VAS and probably PS. This is particularly obvious in
people with age related macular degeneration (AMD). Loss of
function in the centre of the retina, the fovea and macular, creates an
increasing need to use the parafovea and peripheral retina to process text. The
cells and and organisation of the connectivity between cells get larger away
from the fovea.

As such the crowding effect on
the VAS gets bigger and bigger, reducing the VAS AND
increasing the time needed to process the VAS reducing the PS. These difficulties lead to a gradual but
persistent reduction in reading speed/performance with the person taking on
some of the characteristics of a person with ‘developmental dyslexia’.

Raising the font size which is a common response ends up counterproductive,
since that will itself constrain the VAS and the PS ( perceptual span)
ultimately needing a fixation per letter. The person reverts to a reading style
reminiscent of the beginner reader in terms of the eye movement management
demand,

Those working with colour, with adults know
that the phonological components of the reading performance of their clients
increases in a step like way., without any training. The use of a binocular
eyetracker can show the increased number of characters processed per fixation
and hence per second.

The issues to be addressed are these.

Does the colour (chromaticity) affect….

1.The VAS?

2.The crowding which controls the VAS?

3.The time taken to process each VAS?

4.The perceptual span as a
consequence of affecting the VAS and the time to process the VAS?

If we can investigate / answer these issues we will be starting to
make sense of the mechanisms.